GaAs-based InGaAsN quantum well films grown by molecular beam epitaxy are characterized by photoluminescence spectroscopy. InGaAsN with high N concentrations of about 4% requires a low growth temperature of 350° C and minimal As flux. No indications for 3D growth are detected and carrier localization is below 25 meV. Broad area lasers with InGaAsN single quantum wells of different compositions are compared. Threshold current density correlates to room temperature photoluminescence intensity. For an emission wavelength of 1400 nm a threshold current density of 690 A/cm(2) is achieved with 1200 μ m long devices. At 1510 nm a value of 780 A/cm(2) sets a new record for GaAs-based lasers with any kind of active material. © 2005 Elsevier B.V. All rights reserved.